As one method for synthesizing liquid fuels from a natural gas, a GTL (Gas To Liquids: liquid fuel synthesis) technique of reforming a natural gas to produce a synthesis gas containing a carbon monoxide gas (CO) and a hydrogen gas (H2) as the main components, synthesizing hydrocarbons using this synthesis gas as a source gas by the Fischer-Tropsch synthesis reaction (hereinafter referred to as “FT synthesis reaction”), and further hydrogenating and refining the hydrocarbons to produce liquid fuel products, such as naphtha (raw gasoline), kerosene, gas oil, and wax, has recently been developed.
As a synthesis reaction unit which performs the aforementioned FT synthesis reaction, as disclosed, for example, in Patent Document 1, a bubble column type slurry bed FT reaction system in which a solid catalyst is suspended in liquid hydrocarbons to produce a slurry, and a synthesis gas is blown into a reactor containing the slurry, thereby being allowed to undergo the FT synthesis reaction, is suggested.
This type of synthesis reaction unit includes a catalyst separation device which separates the catalyst from the slurry, and performs the operation of extracting a constant amount of liquid hydrocarbons from the slurry in the reactor via the catalyst separation device.
As the aforementioned catalyst separation device, as disclosed, for example, in Patent Document 2, separation device in which a filtering device, or the like, including a filter is provided outside the reactor (external separation method), or provided inside the reactor (internal separation method) are suggested.